On 2015-02-13, Paul <[email protected]> wrote: > On Fri, Feb 13, 2015 at 12:42 AM, William Unruh <[email protected]> wrote: > >> OK, so we seem to have two different sets of experiments with very >> different results. Note that I did not erase the drift file, or restart >> ntpd after my perturbation. >> > > Okay, I offset my clock by 100ms without restarting ntpd. It took about > 100 seconds to reduce that by two orders of magnitude and about 2,800 > seconds to return to O(1) microsecond offset albeit O(10) microseconds of > jitter. Next I'll try Ntimed-client. Perhaps you should redo your > experiment in the modern era. Or quit referring to stale data.
Good suggestion. I had seen nothing however that caused me to think ntpd had changed this part. > > I had a properly set up PPS source to do the comparison. As did I. > > > We have no way of knowing that and the simplest way to get poor recovery is > to use the wrong poll interval with a PPS refclock. Poll 4 for PPS, Poll 6-10 for network. I think the test referred to was using a local network, but by this time it is hard to remember the exact details. Note that since the effective poll interval is 3 higher than the nominal poll interval, and since the convergence time scale is larger than one poll interval, this would give a convergence time of greater than 2^9 sec, or 500 sec (10 min) that is still faster than I was finding. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
